The invention relates to a dead plate arrangement for a glass forming machine with a dead plate which includes a plurality of fields, each of the fields is intended for receiving a hollow glass article to be cooled thereon and is provided with openings for the passage of cooling air.
When determining the cooling capacity to be provided for the hollow glass articles arriving on the dead plate of an I.S. (individual section) glass forming machine, it must be considered that the articles to be cooled are not yet mechanically stable in terms of temperature and that measures have to be taken to achieve a safe standing position on the dead plate. In particular, cooling air that may form an air cushion underneath the articles and causes the articles to migrate or to fall over, etc., must be avoided. Thus, dimensioning the cooling capacity to be provided has to be regarded article-specifically as an optimization process which considers these sometimes countervailing influences.
This object is made difficult due to the fact that in the case of a plurality of articles produced in one station, the temperature of the articles and therefore their mechanical condition varies significantly and, accordingly, the cooling capacity used has to be readjusted repeatedly. This is a process which, in accordance with the frequency of the required adjusting measures, in particular in the case of articles to be changed frequently, can result in downtimes and, subsequent to an adjustment, in damage to the articles in the form of hot cracks which, in certain circumstances, are detected only after many hours, namely at the end of the production process after the articles have cooled down. This problem always occurs when a plurality of hollow glass articles are removed from the station (double gob, triple gob, quad gob operation), the respective temperatures of which articles vary, so that readjustments of the cooling capacity in terms of the time of standing on the dead plate are required.
Known from DE 100 39 343 B4 and U.S. Pat. No. 4,508,557 B are dead plate arrangements in which a plate table intended for standing up hollow glass articles is provided with bores for feeding cooling air. The available cooling capacity is the same for all articles. Individual treatment of an individual article is not provided. The same applies to the dead plate arrangements known from DE 101 01 296 B4 and EP 131 81 16 B1.
The dead plate arrangement known from U.S. Pat. No. 3,510,288 B is characterized by two zones which can be subjected to different amounts of cooling air and/or cooling air pressures. The dead plate arrangement known from U.S. Pat. No. 2,677,919 B is configured in a similar manner. The dead plate arrangements known from these two documents enable implementing a zone-dependent cooling capacity; however, all hollow glass articles standing in one zone are subjected to an equally identical cooling capacity.
Finally, it is known from the document DE 100 06 130 B4 to establish the controller settings for the compressed air supply during the different phases of the blow process in a glass forming machine in an article-specific manner and centralized assisted by a database so that for forming a certain hollow glass article, this data can be used. However, this control does not refer to the setting of the cooling capacity for the articles standing on a dead plate.
The cooling capacity provided according to this prior art for treating the articles standing on a dead plate therefore always acts in an averaged and uniform manner on a plurality of articles. A potential individually differentiated demand of cooling capacity cannot be implemented in this manner.